The subject matter presented herein generally relates to distinguishing intentional from inadvertent device input. More specifically, the subject matter herein relates to differentiating between the characteristics of inadvertent and resting contact with that of purposeful contact in order to activate a touch screen only when the user intentionally presses an area on the touch screen.
The use of touch screens and on-screen keyboards has grown substantially. Today, such technology is present in a wide array of devices, such as cellular phones, tablet computers, audio-visual devices, and interactive kiosk systems. In addition, touch screens have the ability to determine the location and the size of screen contact. For example, certain touch screen technology uses a grid of cells and can sense which cells are being touched at any given point in time. Other touch screens may measure the number of contacted pixels or the physical contact area size, such as the number of millimeters. Another method for determining the area of touch screen contact involves the use of an x-y coordinate system which equates coordinates to pixels or a physical measurement, such as millimeters. Thus, existing touch screen and on-screen keyboard technology is not only able to detect user contact, but may be able to detect the surface area and location of such contact.
As use of touch screens and on-screen keyboards has increased, so have user expectations of the technology. Although touch screens and on-screen keyboards are extremely useful, their use can also be problematic because they are susceptible to activation due to inadvertent contact. Unlike traditional mechanical keyboards with physical buttons or keys, a touch screen or the keys of an on-screen keyboard offer no inherent resistance to activation. As a result, they are much more responsive to unintentional and inadvertent contact. In addition, the resistance force of the key mechanisms on a traditional mechanical keyboard allow the fingers to rest on the keyboard without activating the keys. However, current touch screen and on-screen keyboard technology does not adequately provide similar functionality such that a user may rest their fingers on an on-screen keyboard without generating inadvertent key events.
Existing touch screen and on-screen keyboard technology mainly responds to signal breaks to determine whether an active area has been pressed. As such, inadvertent virtual button and key presses occur easily and frequently. Other touch screen solutions attempt to utilize the size of the contact area to distinguish between, for example, hand and finger contact. However, such solutions are only able to crudely distinguish between large differences in keyboard contact characteristics. Thus, existing solutions are not able to differentiate more precise contact variances, such as that between a finger at rest on an on-screen keyboard and a finger actively pressing a key.